The present invention relates to an electrode position detecting system and method for spot welders. In particular, the invention relates to an electrode position detecting system and method for spot welders in which a welding robot is responsible for carrying, handling and/or manipulation (hereafter collectively "manipulation") of a welding gun that has a pair of relatively movable welding electrodes for pinching, and conducting a welding current through, a spot of work to be thereby welded, wherein a position of a mobile welding electrode (hereafter called "mobile electrode") is detected by a position detector for measurement, analysis and/or control purposes, such as for measurement or analysis of inter-electrode distance or electrode deformation or abrasion, analysis on electrical or mechanical characteristics or performances, correction of electrode feed or inter-electrode distance, compensation such as for an orientation or bend of a manipulated welding gun, or control of welding quality.
A conventional spot welder has an electrode position detecting system in which: a mobile electrode is moved by a servo motor; a sensing element senses the electrode in a position after movement; and a position detector is responsible for servo control data associated with the movement to detect the position of the electrode.
The sensing element is fixed to a measuring installation placed on a foundation on which a welding robot is installed for manipulation of a welding gun.